This recipe comes from the book The great British Bake off How to Bake

For the Base

250g Dark Chocolate digestive biscuits

50g Unsalted Butter melted

For the filling

200g Dark Chocolate chopped

200g Unsalted Butter diced

4 Large eggs at room temperature

100g Light Muscovado sugar

100g Dark Muscovado sugar

200ml Double Cream at room temperature

1 x 23cm spring clip tin , greased

1) Preheat the oven to 180 c. Crush the biscuits to a fine powder in a food processor. Tip into a mixing bowl and stir in the butter until thoroughly combined. Transfer to the prepared tin and press over the base and halfway up the sides using the back of a spoon. chill while making the filling.

2) Put the chocolate and butter into a heatproof bowl and set over a pan of steaming hot but not boiling water. Melt gently , stirring occasionally , then remove the bowl from the pan and leave to cool until needed.

3) Put the eggs into a large mixing bowl and whisk with an electric mixer until frothy. Make sure the sugars are lump free . then add to the eggs and continue whisking until the mixture is very thick and mousse – like. Whisk in the cooled chocolate followed by the cream. When completely combined, pour the filling into the biscuit base.

4) Bake for about 50 mins or until just firm, the filling will have puffed up but will sink as it cools, and may crack a little. Remove from the oven and leave to cool for a few mins, then run a round bladed knife around the inside of the tin to loosen the pie. Leave to cool before unclipping and removing the tin side. Serve at room temp. Any leftover pie will be even better the next day.